Double fan for a heat exchanger, in particular a coolant radiator of a motor vehicle

ABSTRACT

The utilization of double fans for engine cooling of motor vehicles is known. Said fans generate a flow of air which then serves to cool a heat exchanger, in particular a coolant radiator for motor vehicles. The double fan is herein characterized by an optimal use of the surface of the coolant radiator that is to be cooled, so as to be able to achieve a cooling performance as high as possible. The assembly of the double fan has up to now been such that a separate electric motor is provided for each blower. The double fan ( 1 ) for a heat exchanger ( 2 ), in particular a coolant radiator of a motor vehicle, has a first blower ( 4 ) and a second blower ( 5 ). According to the invention, the first driven blower ( 4 ) drives the second blower ( 5 ) by way of a transmission element ( 10 ) provided on the outer surface ( 11 ) of the first blower and an outer surface ( 12 ) of the second blower ( 5 ). The double fan is provided for a heat exchanger, in particular a coolant radiator of a motor vehicle.

BACKGROUND OF THE INVENTION

The present invention relates to a double fan for a heat exchanger, in particular a coolant radiator of a motor vehicle, which double fan has a first fan and a second fan.

It is known to use double fans for engine cooling of motor vehicles. They generate an air flow which then serves to cool a heat exchanger, in particular a coolant radiator for motor vehicles. Here, the double fan is distinguished by optimum utilization of the face to be cooled of the coolant radiator, in order thus for it to be possible to achieve as high a cooling performance as possible. The double fan has been constructed up to now such that a dedicated electric motor is provided for each fan.

SUMMARY OF THE INVENTION

In contrast, the double fan according to the invention for a heat exchanger, in particular a coolant radiator of a motor vehicle, has the advantage of a considerably simplified and more compact construction and, in particular, that the production costs can be reduced greatly. A previously necessary second electric motor can therefore be dispensed with. Moreover, the development of noise of the double fan overall can advantageously be reduced.

A transmission element can thus be formed in a simple way by a first toothing system which is formed on the circumferential face of the first fan and by a second toothing system which is correspondingly formed on the circumferential face of the second fan, which toothing systems both engage into one another for torque transmission.

Satisfactory torque transmission can also be achieved if the transmission element is formed by a first circumferential element which surrounds the first circumferential face and by a second circumferential element which surrounds the second circumferential face, which circumferential elements both make torque transmission possible by means of a frictional connection and/or by means of a positively locking connection.

In one advantageous embodiment, the first and second circumferential elements can comprise belt or rubber elements which are tensioned over the circumferential face of the fans and, bearing against one another, both make torque transmission possible as a result of a frictional connection.

In a further advantageous embodiment, the first and second circumferential elements can comprise frictional coatings which are correspondingly applied to the circumferential faces of the fans and make torque transmission possible as a result of a frictional connection.

In a further advantageous embodiment, the first and second circumferential elements can comprise toothed belts which are tensioned over the circumferential face of the fans and engage into one another with their profile on the outer side and make torque transmission possible as a result of a positively locking connection.

In a further advantageous embodiment, the first and second circumferential elements can comprise profiled coatings which are applied to the circumferential faces of the fans and make torque transmission possible as a result of a positively locking connection.

It is advantageous in terms of production technology to simply spray the profiled coatings onto the circumferential faces.

BRIEF DESCRIPTION OF THE_DRAWINGS

Exemplary embodiments of the invention are explained in greater detail in the following description and clarified further using the drawings.

In the drawings:

FIG. 1 shows a simplified plan view of the double fan according to the invention, a transmission region being indicated by A, illustrated bordered by a dashed line,

FIG. 2 shows, in an enlarged illustration, the transmission region A with a viewing direction from the front toward the teeth of a provided toothing system for the fans,

FIG. 3 shows the transmission region A with a viewing direction toward the circumferential face or the fan belt of the fan according to an alternative embodiment,

FIG. 4 shows the transmission region A with a viewing direction toward the circumferential face or the fan belt of the fan according to a further alternative embodiment,

FIG. 5 shows a further embodiment of the double fan according to the invention, in which belt or rubber elements are provided, and

FIG. 6 shows a further embodiment of the double fan according to the invention, in which toothed belts are provided.

DETAILED DESCRIPTION

FIG. 1 shows a plan view of a double fan 1 according to the invention for a heat exchanger 2. The heat exchanger 2, also called heat transmitter, is, for example, a conventional coolant radiator of a motor vehicle, as is usually provided for engine cooling. The double fan 1 has two fans 4, 5, a driven first fan 4 being mounted in a known way on an electric motor. The electric motor is indicated diagrammatically in FIG. 1 by a square 6. The second fan 5 is mounted on a provided bearing block 7 which is indicated diagrammatically in FIG. 1 by a circle. Both fans 4, 5 are arranged in such a way that they preferably make contact with one another on the circumferential side at a single point in the center (intersecting point of the diagonal) of the rectangular heat exchanger 2. This point or the transmission region is indicated in FIG. 1 by A, bordered by a dashed line.

It is then provided according to the invention to drive the second fan 5 directly via the first fan 4 which is driven by the electric motor 6, with the result that there is a positive drive for the second fan 5. The second fan 5 simply runs together with the first fan 4. As a result of the second freewheeling fan 5 running together with the first fan 4, it is then possible to dispense with a previously necessary separate electric drive or motor for the second fan 5 and to replace it with a simple bearing point. As a result of this construction, approximately ¾ of the costs for an otherwise necessary second electric motor of the second fan 5 can be saved. However, the additional expenditure for the bearing block 7 and the structural measures for both fans 4, 5 use approximately ¼ of the saved costs. Moreover, it is advantageous that a construction of the two fans 4, 5 in a common frame can be dispensed with.

To this end, there are several possibilities for the positive drive of the second fan 5. A common feature is a transmission element 10 between the fans 4, 5, which transmission element 10 assumes the transmission of the torque of the first fan 4 to the second fan 5. Here, according to the invention, the transmission element 10 is provided or formed on a circumferential face 11 of the first fan 4 and a circumferential face 12 of the second fan 5. As FIG. 2 shows in greater detail in an enlarged illustration of the transmission region A with a viewing direction from the front, the transmission element 10 can be configured in the form of a toothing system, a first toothing system 15 for the first fan 4 and a second toothing system 16 for the second fan 5. By means of the transmission element 10 or the toothing system 15, 16, a circumferential force and a normal force can be transmitted from the first fan 4 to the second fan 5 as far as possible without noise. A toothing system 15, 16 is formed in each case both on the circumferential face 11 of the first fan 4 and on the circumferential face 12 of the second fan 5, whereupon there are two gearwheels of a gear mechanism which engage into one another.

Here, the profile of the toothing system 15, 16 can correspond to that of a gearwheel, as FIG. 3, an illustration of the transmission region A with a viewing direction toward the circumferential face 11 of the fan 4, shows in greater detail. However, it is also possible, as FIG. 2, an illustration of the transmission region A with a viewing direction toward the circumferential face 11 of the fan 4, shows in greater detail to provide a changing toothing system 15 which is offset in the circumferential direction with correspondingly offset teeth for the profile. The toothing system 16 for the second fan 5 would then also be configured in a complementary way.

The circumferential face 11, 12, which is cylindrical at least in regions, of each fan 4, 5 surrounds its blades 7, 8 on the outer side, and can therefore also be called outer belt or fan belt. The fans 4, 5 are preferably axial fans which can also be called circumferential fans on account of the cylindrical circumferential face 11, 12. The outer belt 11, 12 which surrounds the blades 7, 8 is usually provided, in order for it to be possible to reduce air turbulences of the fan vanes or blades 7, 8.

In one modification, the transmission element 10 can also be formed by a first circumferential element 21 which surrounds the first circumferential face 11 and by a second circumferential element 22 which surrounds the second circumferential face 12, which circumferential elements 21, 22 then make torque transmission possible by means of a frictional connection and/or by means of a positively locking connection. Thus, in an embodiment according to FIG. 5, the first and second circumferential elements 21, 22 can comprise belt or rubber elements 25, 26 which are in each case tensioned over the circumferential face 11, 12 of the fans 4, 5 and which then, bearing against one another in a lightly pressed manner, bring about torque transmission from the driven first fan 4 to the second fan 5 as a result of a frictional connection.

A further possibility comprises configuring the first and second circumferential elements 21, 22 in the form of a frictional coating (not shown in greater detail) which is applied correspondingly as it were as a second layer to the circumferential faces 11, 12 and then brings about a frictional connection and therefore torque transmission from the driven first fan 4 to the second fan 5, likewise by both circumferential faces 11, 12 being pressed onto one another. The fans 4, 5 including the outer belt are usually produced from plastic. The frictional coating can, for example, be simply sprayed onto the circumferential faces 11, 12.

It is also conceivable, as FIG. 6 shows, to provide toothed belts 27, 28 for the first and second circumferential elements 21, 22, which toothed belts 27, 28 are tensioned over the circumferential face 11, 12 of the fans 4, 5 and engage into one another with their toothed profile on the outer side, in order to make torque transmission possible as a result of a positively locking connection. It is also possible, instead of the toothed belt, to apply the corresponding profile itself directly onto the circumferential faces 11, 12. To this end, profiled coatings which are shown by way of example in FIGS. 3 and 4 can be provided as toothing systems 15, 16, which profiled coatings are applied to the circumferential face 11, 12 and make torque transmission possible as a result of a positively locking connection. In a simple way, the profiled coatings can be sprayed onto the circumferential faces 11, 12 which afterward have, for example, structures according to FIGS. 3 and 4. 

1. A double fan for a heat exchanger, which double fan has a first fan and a second fan, characterized in that the first fan (4) is driven and drives the second fan (5) via a transmission element (10) which is provided on a circumferential face (11) of the first fan (4) and a circumferential face (12) of the second fan (5).
 2. The double fan as claimed in claim 1, characterized in that the transmission element (10) is formed by a first toothing system (15) which is formed on the circumferential face (11) of the first fan (4) and by a second toothing system (16) which is correspondingly formed on the circumferential face (12) of the second fan (5), which toothing systems (15, 16) both engage into one another for torque transmission.
 3. The double fan as claimed in claim 1, characterized in that the transmission element (10) is formed by a first circumferential element (21) which surrounds the first circumferential face (11) and by a second circumferential element (22) which surrounds the second circumferential face (12), which circumferential elements (21, 22) both make torque transmission possible by means of at least one of a frictional connection and a positively locking connection.
 4. The double fan as claimed in claim 3, characterized in that the first and second circumferential elements (21, 22) comprise at least one of belt or rubber elements (25, 26) which are tensioned over the respective circumferential faces (11, 12) of the fans (4, 5) and, bearing against one another, both make torque transmission possible as a result of a frictional connection.
 5. The double fan as claimed in claim 3, characterized in that the first and second circumferential elements (21, 22) comprise frictional coatings which are applied to the respective circumferential faces (11, 12) of the fans (4, 5) and make torque transmission possible as a result of a frictional connection.
 6. The double fan as claimed in claim 3, characterized in that the first and second circumferential elements (21, 22) comprise toothed belts (27, 28) which are tensioned over the respective circumferential faces (11, 12) of the fans (4, 5) and engage into one another with their profile on an outer side and make torque transmission possible as a result of a positively locking connection.
 7. The double fan as claimed in claim 3, characterized in that the first and second circumferential elements (21, 22) comprise profiled coatings which are applied to the respective circumferential faces (11, 12) of the fans (4, 5) and make torque transmission possible as a result of a positively locking connection.
 8. The double fan as claimed in claim 7, characterized in that the profiled coatings are sprayed onto the circumferential faces (11, 12).
 9. The double fan as claimed in claim 1, characterized in that the heat exchanger is a coolant radiator of a motor vehicle. 